Field
The present disclosure relates to network management. More specifically, the present disclosure relates to a method and system for efficient failover in a multicast distribution tree.
Related Art
The exponential growth of the Internet has made it a popular delivery medium for multimedia applications, such as video on demand and television. Such applications have brought with them an increasing demand for bandwidth. As a result, equipment vendors race to build larger and faster switches with versatile capabilities, such as multicasting, to move more traffic efficiently. However, the size of a switch cannot grow infinitely. It is limited by physical space, power consumption, and design complexity, to name a few factors. Furthermore, switches with higher capability are usually more complex and expensive. More importantly, because an overly large and complex system often does not provide economy of scale, simply increasing the size and capability of a switch may prove economically unviable due to the increased per-port cost.
One way to meet this challenge is to interconnect a number of switches in a multicast tree to support a large number of multicast users of a multicast group. When such a switch goes through a recovery (e.g., from a failure), the switch reconciles the local multicast states. Usually, for reconciliation, the switch relies on the neighbor switches of the multicast tree to send the multicast states (e.g., the join messages for the multicast group). However, this reconciliation procedure is not deterministic because the switch is unaware of whether a neighbor switch has completed sending its states. Hence, the switch usually waits for a finite period of time to completely rebuild its local multicast states, leading to delay and reduced performance.
While multicast brings many desirable features to a network, some issues remain unsolved in efficient recovery in a multicast network.